Space between chamber and breach block

mrerick · 12-25-2012, 12:27 PM

I recently helped analyze a pair of cartridge failures that relate to Rick W.'s discussion above.

The 9mm Luger cartridge headspaces on it's case mouth.

When the cartridge is fired, it must be properly supported with it's base supported by the breech face and it's sides supported by the chamber walls.

Normally, the extractor engages in the rim, and tends to pull the cartridge base up against the breech face.

If a 9mm cartridge case is short enough (and out of specs) the cartridge may be pushed too far into the chamber, the extractor not properly engaged in the rim, and a large gap left between the cartridge base and the breech face.

I think that this is what happened here (on both a Luger and a p.38). The result can be catastrophic:

See post #56 in this thread over on Jan Still's forum:

http://luger.gunboards.com/showthrea...oday-!!!/page6

- - - - - -

I've always wondered about the variation of space at the breech end of the toggle train in our Lugers, and it's potential for trouble.

Marc

12-25-2012, 12:27 PM	#12
mrerick Super Moderator - Patron LugerForum Life Patron Join Date: Dec 2009 Location: Eastern North Carolina, USA Posts: 3,925 Thanks: 1,376 Thanked 3,140 Times in 1,520 Posts	I recently helped analyze a pair of cartridge failures that relate to Rick W.'s discussion above. The 9mm Luger cartridge headspaces on it's case mouth. When the cartridge is fired, it must be properly supported with it's base supported by the breech face and it's sides supported by the chamber walls. Normally, the extractor engages in the rim, and tends to pull the cartridge base up against the breech face. If a 9mm cartridge case is short enough (and out of specs) the cartridge may be pushed too far into the chamber, the extractor not properly engaged in the rim, and a large gap left between the cartridge base and the breech face. I think that this is what happened here (on both a Luger and a p.38). The result can be catastrophic: See post #56 in this thread over on Jan Still's forum: http://luger.gunboards.com/showthrea...oday-!!!/page6 - - - - - - I've always wondered about the variation of space at the breech end of the toggle train in our Lugers, and it's potential for trouble. Marc __________________ Igitur si vis pacem, para bellum - - Therefore if you want peace, prepare for war.